function qiehuan(num){
    for(var id = 0;id<=8;id++) 		{
        if(id==num) {
            document.getElementById("qh_con"+id).style.display="block";
            document.getElementById("mynav"+id).className="nav_on";
        } else {
            document.getElementById("qh_con"+id).style.display="none";
            document.getElementById("mynav"+id).className=""; }
    }
}
